I need some support. I desired convert a variable String to Date. The variable Date should be format dd-MM-yyyy.
import java.util.Date;
....
...
String a = "2022-05-12";
Date b; // should be dd-MM-yyyy
do some to format...
return b; // return b with format dd-MM-yyyy, remember this variable is type Date no String
I was trying to do something but the format obtained is not the desired one.
LocalDate
.parse( "2022-05-12" )
.format(
DateTimeFormatter.ofPattern( "dd-MM-uuuu" )
)
12-05-2022
Use modern java.time classes. Never use the terrible Date, Calendar, SimpleDateFormat classes.
Your input conforms to ISO 8601 standard format used by default in the java.time classes for parsing/generating text. So no need to specify a formatting pattern.
LocalDateParse your date-only input as a date-only object, a LocalDate.
String input = "2022-05-12" ;
LocalDate ld = LocalDate.parse( input ) ;
To generate text in your desired format, specify a formatting pattern.
DateTimeFormatter f = DateTimeFormatter.ofPattern( "dd-MM-uuuu" ) ;
String output = ld.format( f ) ;
Rather than hardcode a particular pattern, I suggest learning to automatically localize using DateTimeFormatter.ofLocalizedDate.
All this has been covered many many times already on Stack Overflow. Always search thoroughly before posting. Search to learn more.
What you are doing is converting from string to date. It seems that you want it to PRINT the date in a specific format.
Where is an example of how to do it:
DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
Date date = new Date();
System.out.println(dateFormat.format(date)); //2022/05/18 00:18:43
Date, you need to format it again. You can have a look at the implementation of thetoStringmethod. If your are only interested in the days, LocalDate might be a good pick.Datehas only a one format when using itstoStringmethod - that format cannot be changed - a formatter must be used toformatit into a string. Please do not upload images of code/data/errors when asking a question.Daterepresents an instant in time, not a date. It's very unfortunately named. You should be usingjava.time.LocalDate, orjava.time.ZonedDateTime, or similar. None of those represent a format. To 'print' such an object with a specific format, pass it to a formatter which gives you a string.SimpleDateFormatorDate, they are out-of-date, use thejava.time.*APIs instead; 2. Dates (in general) are simply containers for the amount of time which has passed since a given point in time (ie the Unix epoch), they don't, by design, have a concept of "format", thetoStringimplementation is simply there to provide information, this is what formatters are used for, you format the date/time object to aString